The invention relates to a surgical tensioning device for tensioning a tensioning means securing bone elements in position, comprising a handle and a slide which is movable back and forth in tensioning direction and on which a holding element securing the tensioning means on the slide during a movement of the slide in tensioning direction is held.
Tensioning devices of this type are used, in particular, with the application of so-called cerclage devices, with the aid of which the bone elements to be secured in position, for example, during the repositioning of oblique fractures are wrapped around by a tensioning means, for example a metal strap or a wire cable, and subsequently connected to one another and secured in position by tensioning the tensioning means. The cerclage devices are customarily premanufactured such that a first end of, for example, a wire cable is fixed to a cerclage locking member and the second, free end of the wire cable can be guided around the bone elements to be fixed in position, thereby forming a loop, and subsequently through a through bore in the cerclage locking member. With the aid of the tensioning device, the wire cable can subsequently be tensioned, wherein the housing of the tensioning device is supported on the cerclage locking member.
Surgical tensioning devices are known from U.S. Pat. Nos. specifications 5,116,340 and 4,966,600, in which the wire cable is tensioned by winding around a capstan. The capstan is held for rotation on a handle of a pair of pliers attachable to the cerclage locking member. In order to tension the wire cable, the mouth of the pliers must be clamped to the cerclage locking member and the free end of the wire cable subsequently threaded into the capstan, onto which the wire cable is then wound by turning a handle. The handling of this surgical tensioning device is thus rather complicated.
A difficult and time-consuming handling is a great disadvantage, in particular, when a larger number of cerclage devices are utilized during an operation and these are first of all fixed in position only temporarily in order to be able to subsequently correct the position of the bone elements to be fixed in position with cerclage devices which have already been applied. This operating technique is used, for example, in the field of spine surgery. In order to be able to carry out a correction of the spine by tensioning the cerclage devices, an intraoperative, temporary fixing in position of the cerclage devices must be possible which allows subsequent tensioning and correction. As a result, the surgical tensioning device must often be reapplied to the loose ends of the wire cable. The use of a capstan for winding and tensioning the wire cable results in a time-consuming operating technique.
Tensioning devices with two telescoping housing sections are known (U.S. Pat. No. 5,312,410, Wo 95/22294), wherein a first housing section can be supported on the cerclage locking member and a second housing section is displaceable in tensioning direction. The free end of the wire cable is guided axially through the tensioning device and secured on the second housing section. A construction of this type has, in particular, the disadvantage that the wire cable can be tensioned only to such an extent until the maximum path of displacement of the second housing section has been reached.
Finally, surgical tensioning devices are also known (U.S. Pat. No. 5,057,113, WO 95/05127), in which a slide, which is displaceable in tensioning direction and to which the free end of the wire cable can be secured by means of a holding element, is used instead of two telescoping housing sections. The holding element is designed such that the wire cable is fixed in position on the slide during a movement of the slide in tensioning direction. These tensioning devices are also subject to the disadvantage described above that the tensioning of the wire cable which can be achieved is limited to the path of displacement of the slide.